The USB is not set up as a host, so it won't work with a keyboard plugged into it. Some Bluetooth keyboards work, but the firmware only accepts certain key presses from them (corresponding to button presses on the device). I don't think anyone has been able to use a keyboard to type notes, say.

If you just want a decent terminal, then there are a few available that work over WiFi. You can attach from your desktop and type comfortably from there. See Paola's sticky thread on stuff for the "new" Pro devices to find links to a collection of shell applications (and other fun stuff).